This document provides an overview of anatomy and physiology. It begins by defining anatomy as the study of structure and physiology as the study of function. It describes different methods of studying anatomy, including surface observation, dissection, palpation, auscultation, and percussion. It then discusses the hierarchy of biological complexity from molecules to cells to tissues to organs to organ systems. The document also defines and provides examples of organs, tissues, organelles, and molecules. It lists and describes the 11 major organ systems of the human body. Finally, it introduces some key anatomical concepts and terminology used to describe the human body.

1. ANATOMY & PHYSIOLOGY 101

2. What do you expect you will learn in this module?

3. Anatomyis the study of structure and Physiologyis the study of function

4. Anatomy—The Study of FormThe simplest way to study human anatomy is the observation of surface structure, for example in performing a physical examination or making a clinical diagnosis from surface appearance. But a deeper understanding of the body depends on dissection—the careful cutting and separation of tissues to reveal their relationships.Dissection, of course, is not the method of choice when studying a living person!

5. Physical examinations involve not only looking at the body for signs of normalcy or disease but also touching and listening to it.Palpation is feeling structure with the fingertips, such as palpating a swollen lymph node or taking a pulse.Auscultationis listening to the natural sounds made by the body, such as heart and lung sounds. In Percussion, the examiner taps on the body and listens to the sound for signs of abnormalities such as pockets of fluid or air.Structure that can be seen with the naked eye, whether by surface observation or dissection, is called gross anatomy

6. Physiology—The Study of FunctionPhysiology uses the methods of experimental science.It has many subdisciplines such as neurophysiology (physiology of the nervous system), endocrinology (physiology of hormones), and pathophysiology(mechanisms of disease).

7. The Hierarchy of ComplexityThe organism is composed of organ systems, organ systems are composed of organs, organs are composed of tissues, tissues are composed of cells, cells are composed (in part) of organelles, organelles are composed of molecules, and molecules are composed of atoms.The organism is a single, complete individual.

8. OrgansAn organ is a structure composed of two or more tissue types that work together to carry out a particular function. Organs have definite anatomical boundaries and are visibly distinguishable from adjacent structures. Most organs and higher levels of structure are within the domain of gross anatomy. However, there are organs within organs— the large organs visible to the naked eye often contain smaller organs visible only with the microscope. The skin, for example, is the body’s largest organ. Included within it are thousands of smaller organs: each hair, nail, gland, nerve, and blood vessel of the skin is an organ in itself.

9. Tissue A tissue is a mass of similar cells and cell products that forms a discrete region of an organ and performs a specific function. The body is composed of only four primary classes of tissue—epithelial, connective, nervous, and muscular tissues.

10. Cells Cells are the smallest units of an organism that carry out all the basic functions of life; nothing simpler than a cell is considered alive. A cell is enclosed in a plasma membrane composed of lipids and proteins. Most cells have one nucleus, an organelle that contains its DNA.

11. Organelles Organelles are microscopic structures in a cell that carry out its individual functions. Examples include mitochondria, centrioles, and lysosomes

12. Molecules Organelles and other cellular components are composed of molecules. The largest molecules, such as proteins, fats, and DNA, are called macromolecules. A molecule is a particle composed of at least two atoms, the smallest particles with unique chemical identities.

13. Organ systemAn organ system is a group of organs with a unique collective function. The human body has 11 organ systems. In groups see if you can tell me what the 11 systems are and describe the principle organs and functions of these systems.

14. 1. Integumentary systemPrincipal organs: Skin, hair, nails,cutaneous glandsPrincipal functions: Protection, waterretention, thermoregulation, vitamin Dsynthesis, cutaneous sensation,nonverbal communication

15. 2. Skeletal systemPrincipal organs: Bones, cartilages,LigamentsPrincipal functions: Support, movement,protective enclosure of viscera, bloodformation, electrolyte and acid-basebalance

16. 3. Muscular systemPrincipal organs: Skeletal musclesPrincipal functions: Movement,stability, communication, control ofbody openings, heat production

17. 4. Nervous systemPrincipal organs: Brain, spinal cord,nerves, gangliaPrincipal functions: Rapid internalcommunication and coordination,sensation

18. 5. Endocrine systemPrincipal organs: Pituitary gland,pineal gland, thyroid gland,parathyroid glands, thymus, adrenalglands, pancreas, testes, ovariesPrincipal functions: Internalchemical communication andcoordination

19. 6.Circulatory systemPrincipal organs: Heart, blood vesselsPrincipal functions: Distribution ofnutrients, oxygen, wastes, hormones,electrolytes, heat, immune cells, andantibodies; fluid, electrolyte, and acidbasebalance

20. 7. Lymphatic systemPrincipal organs: Lymph nodes,lymphatic vessels, thymus, spleen,TonsilsPrincipal functions: Recovery of excesstissue fluid, detection of pathogens,production of immune cells, defense

21. 8. Respiratory systemPrincipal organs: Nose, pharynx,larynx, trachea, bronchi, lungsPrincipal functions: Absorption ofoxygen, discharge of carbon dioxide,acid-base balance, speech

22. 9. Urinary systemPrincipal organs: Kidneys, ureters,urinary bladder, urethraPrincipal functions: Elimination ofwastes; regulation of blood volumeand pressure; stimulation of redblood cell formation; control offluid, electrolyte, and acid-basebalance; detoxification

23. 10. Digestive systemPrincipal organs: Teeth, tongue,salivary glands, esophagus, stomach,small and large intestines, liver,gallbladder, pancreasPrincipal functions: Nutrientbreakdown and absorption; liverfunctions include metabolism ofcarbohydrates, lipids, proteins,vitamins, and minerals, synthesis ofplasma proteins, disposal of drugs,toxins, and hormones, and cleansingof blood

24. 11. Reproductive systemPrincipal organs: Testes, epididymides,spermatic ducts, seminal vesicles,prostate gland, bulbourethral glands,penisPrincipal functions: Production anddelivery of spermPrincipal organs: Ovaries, uterinetubes, uterus, vagina, vulva, mammaryglandsPrincipal functions: Production ofeggs, site of fertilization and fetaldevelopment, fetal nourishment, birth,lactation

25. Characteristics of LifeOrganization Living things exhibit a far higher level of organization than the nonliving world around them. They expend a great deal of energy to maintain order and a breakdown in this order is accompanied by disease and often death.Cellular CompositionLiving matter is always compartmentalized into one or more cells

26. Metabolism and excretion. Living things take inmolecules from the environment and chemically change them into molecules that form their own structures, control their physiology, or provide them with energy. Metabolismis the sum of all this internal chemical change. It consists of two classes of reactions: anabolism, in which relatively complex molecules are synthesized from simpler ones (for example, protein synthesis), and catabolism, in which relatively complex molecules are broken down into simpler ones (for example, protein digestion). Metabolism inevitably produces chemical wastes, some of which are toxic if they accumulate

27. Metabolism therefore requires excretion, theseparation of wastes from the tissues and their elimination from the body. There is a constant turnover of molecules in the body; few of the molecules now in your body have been there for more than a year. It is food for thought that although you sense a continuity of personality and experience from your childhood to the present, nearly all of your body has been replaced within the past year

28. Responsiveness and movement. The ability of organisms to sense and react to stimuli (changes in their environment) is called responsiveness, irritability, or excitability. It occurs at all levels from the single cell to the entire body, and it characterizes all living things from bacteria to you. Responsiveness is especially obvious in animals because of nerve and muscle cells that exhibit high sensitivity to environmental stimuli, rapid transmission of information, and quick reactions. Most living organisms are capable of self-propelled movement from place to place, and all organisms and cells are at least capable of moving substances internally, such as moving food along the digestive tract or moving molecules and organelles from place to place within a cell.

29. Homeostasis. While the environment around an organism changes, the organism maintains relatively stable internal conditions. This ability to maintain internal stability, called homeostasis, is explored in more depth later on in the course.

30. Physiological variables differ with sex, age, weight, diet, degree of physical activity, and environment, among other things. In an introductory textbook states a typical human heart rate, blood pressure, red blood cell count, or body temperature, it is generally assumed that such values are for a healthy young adult unless otherwise stated. A point of reference for such general values is the reference man and reference woman. The reference man is defined as a healthy male 22 years old, weighing 70 kg (154 lb), living at a mean ambient (surrounding) temperature of 20C, engaging in light physical activity, and consuming 2,800 kilocalories (kcal) per day. The reference woman is the same except for a weight of 58 kg (128 lb) and an intake of 2,000 kcal/day.

31. Anatomical TerminologyOne of the greatest challenges faced by students of anatomy and physiology is the vocabulary. In this book, you will encounter such Latin terms as corpus callosum (a brain structure), ligamentumarteriosum (a small fibrous band near the heart), and extensor carpiradialislongus (a forearm muscle). You may wonder why structures aren’t named in “just plain English,” and how you will ever remember such formidable names

32. The major features of human gross anatomy have standard international names prescribed by a book titled the TerminologiaAnatomica (TA). The TA was codified in 1998 by an international body of anatomists, the Federative Committee on Anatomical Terminology, and approved by professionalassociations of anatomists in more than 50 countries.About 90% of today’s medical terms are formed from just 1,200 Greek and Latin roots. Scientific investigation began in ancient Greece and soon spread to Rome. The Greeks and Romans coined many of the words still used in human anatomy today: uterus, prostate, cerebellum, diaphragm, sacrum, amnion, and others.

33. Analyzing Medical TermsThe task of learning medical terminology seems overwhelming at first, but there is a simple trick to becoming more comfortable with the technical language of medicine.People who find scientific terms confusing and difficult to pronounce, spell, and remember usually feel more confident once they realize the logic of how terms are composed.A term such as hyponatremia is less forbidding once we recognize that it is composed of three common word elements

34. hypo- (below normal), natri- (sodium), and –emia(blood condition). Thus, hyponatremia is a deficiency of sodium in the blood.Those word elements appear over and over in many other medical terms: hypothermia, natriuretic, anemia, and so on. Once you learn the meanings of hypo-, natri-, and -emia, you already have the tools at least to partially understand hundreds of other biomedical terms

35. Root (stem) Scientific terms are typically composed of one or more of the following elements: At least one root (stem) that bears the core meaning of the word. In cardiology, for example, the root is cardi- (heart). Many words have two or more roots. In cytochrome, the roots are cyt- (cell) and chrom- (color)

36. Combining Combining vowels that are often inserted to join roots and make the word easier to pronounce. In cytochrome, for example, the first o is a combining vowel. Although o is the most common combining vowel, all vowels of the alphabet are used in this way, such as a in ligament, e in vitreous,, u in ovulation, and y in tachycardia.

37. PrefixA prefix may be present to modify the core meaning of the word. For example, gastric (pertaining to the stomach or to the belly of a muscle) takes on a wide variety of new meanings when prefixes are added to it: epigastric (above the stomach),hypogastric (below the stomach)endogastric (within the stomach)and digastric (a muscle with two bellies).

38. SuffixA suffix may be added to the end of a word to modify its core meaning. For example, microscope, microscopy, microscopic, and microscopist have different meanings because of their suffixes alone. Often two or more suffixes, or a root and suffix, occur together so often that they are treated jointly as a compound suffix; for example, log (study) y (process) form the compound suffix -logy (the study of).

39. To summarize these basic principles, consider the word gastroenterology, a branch of medicine dealing with the stomach and small intestine. It breaks down into: gastro/entero/logygastro a combining form meaning “stomach”entero a combining form meaning “small intestine”logy a compound suffix meaning “the study of”“Dissecting” words in this way and paying attention to the word-origin footnotes throughout this course will help make you more comfortable with the language ofanatomy.

40. Anatomical Position Anatomical position is a stance in which a person stands erect with the feet flat on the floor, arms at the sides, and the palms, face, and eyes facing forward. This position provides a precise and standard frame of reference for anatomical description and dissectionWithout such a frame of reference, to say that a structure such as the sternum, thymus, or aorta is “above the heart” would be vague, since it would depend on whether the subject was standing, lying face down, or lying face up.

41. Unless stated otherwise, assume that all anatomical descriptions refer to anatomical position. Bear in mind that if a subject is facing you in anatomical position, the subject’s left will be on your right and vice versa.In most anatomical illustrations, for example, the left atrium of the heart appears toward the right side of the page, and while the appendix is located in the right lower quadrant of the abdomen, it appears on the left side of most illustrations

42. The forearm is said to be supine when the palms face up or forward and prone when they face down or rearward. The difference is particularly important to descriptions of anatomy of this region. In the supine position, the two forearm bones (radius and ulna) are parallel and the radius is lateral to the ulna. In the prone position, the radius and ulna cross; the radius is lateral to the ulna at the elbow but medial to it at the wrist. Descriptions of nerves, muscles, blood vessels, and other structures of the forearm assume that the forearm is supine. (Supine also means lying face up and prone also means lying face down.)RadiusUlnaPositions of the Forearm. When the forearm issupine, the palm faces forward; when prone, it faces rearward. Note the differences in the relationship of the radius to the ulna.

43. Anatomical PlanesMany views of the body are based on real or imaginary “slices” called sections or planes. “Section” implies an actual cut or slice to reveal internal anatomy, whereas “plane” implies an imaginary flat surface passing through the body. The three major anatomical planes are sagittal, frontal, and transverseFrontal planeTransverse planeMedian [Mid-Sagittal] plane

44. A sagittal plane passes vertically through the body or an organ and divides it into right and left portions. The sagittal plane that divides the body or organ into equal haves is also called the median (midsagittal) plane. The head and pelvic organs are commonly illustrated on the median planeMedian [Mid-Sagittal] plane

45. A frontal (coronal) plane also extends vertically, but it is perpendicular to the sagittal plane and divides the body into anterior (front) and posterior (back) portions. A frontalsection of the head, for example, would divide it into one portion bearing the face and another bearing the back of the head. Contents of the thoracic and abdominal cavities are most commonly shown in frontal section.Frontal Plane

46. A transverse (horizontal) plane passes across the body or an organ perpendicular to its long axis therefore, it divides the body or organ into superior (upper) and inferior (lower) portions. CT scans are typically transverse sectionsTransverse Plane

47. Views of the Body in the Three Primary Anatomical Planes(a) (b) (c) (a) Sagittal section of the pelvic region.(b) Frontal section of the thoracic region. (c) Transverse section of the head at the level of the eyes.

48. Directional Terms in Human Anatomy

49. Surface AnatomyKnowledge of the external anatomy and landmarks of the body is important in performing a physical examination and many other clinical procedures. For purposes of study, the body is divided into two major regions called the axial and appendicular regions. Smaller areas within the major regions are described

50. Axial RegionThe axial region consists of the head, neck (cervical2 region), and trunk. The trunk is further divided into the thoracic region above the diaphragm and the abdominalregion below it.One way of referring to the locations of abdominal structures is to divide the region into quadrants. Two perpendicular lines intersecting at the umbilicus (navel) divide the abdomen into a right upper quadrant (RUQ), right lower quadrant (RLQ), left upper quadrant (LUQ), and left lower quadrant (LLQ). The quadrant scheme is often used to describe the site of an abdominal pain or abnormality.

51. Organisation of the BodyRightupperquadrantLeftupperquadrantRightlowerquadrantLeftlowerquadrantSternumLungStomachURQULQ10th Costal CartilageLLQLRQFemur

52. Appendicular RegionThe appendicular region of the body consists of the appendages (also called limbs or extremities): the upper limbs and the lower limbs. The upper limb includes the brachium (arm), antebrachium (forearm), carpus (wrist), manus (hand), and digits (fingers). The lower limb includes the thigh, crus (leg), tarsus (ankle), pes (foot), and digits (toes). In strict anatomical terms, “arm” refers only to that part of the upper limb between the shoulder and elbow. “Leg” refers only to that part of the lower limb between the knee and ankle.

53. Body Cavities and MembranesThe body is internally divided into two major body cavities, dorsal and ventral . The organs within them are called the viscera. Various membranes line the cavities, cover the viscera, and hold the viscera in place.

54. Dorsal Body CavityThe dorsal body cavity has two subdivisions: the cranial cavity, which is enclosed by the cranium (braincase) and contains the brain, and the vertebral canal, which is enclosed by the vertebral column (backbone) and contains the spinal cord. The dorsal body cavity is lined by three membrane layers called the meninges . Among other functions, the meninges protect the delicate nervous tissue from the hard protective bone that encloses it.

55. Ventral Body Cavity During embryonic development, a space called the coelom (SEE-loam) forms within the trunk and eventually gives rise to the ventral body cavity. This cavity later becomes partitioned by a muscular sheet, the diaphragm, into a superior thoracic cavity and an inferior abdominopelvic cavity. The thoracic and abdominopelvic cavities are lined with thin serous membranes. These membranes secrete a lubricating film of moisture similar to blood serum (hence the name serous).

57. Thoracic CavityThe thoracic cavity is divided into right, left, and medial portions by a partition called the mediastinum. The right and left sides contain the lungs and are lined by a two-layered membrane called the pleura. The outer layer, or parietalpleura, lies against the inside of the rib cage; the inner layer, or visceral pleura, forms the external surface of the lung. The narrow, moist space between the visceral and parietal pleurae is called the pleural cavity. It is lubricated by a slippery pleural fluid.The medial portion, or mediastinum, is occupied by the esophagus and trachea, a gland called the thymus, and the heart and major blood vessels connected to it. The heart is enclosed by a two-layered membrane called the pericardium. The visceral pericardium forms the heart surface, while the parietal pericardium is separated from it by a space called the pericardial cavity. This space is lubricated by pericardial fluid.

58. Abdominopelvic Cavity The abdominopelvic cavity consists of the abdominal cavity above the brim of the pelvis and the pelvic cavity below the brim (see fig. A.16). The abdominal cavity contains most of the digestive organs as well as the kidneys and ureters. The pelvic cavity is markedly narrower and its lower end tilts posteriorly (see fig. A.7a). It contains the distal part of the large intestine, the urinary bladder and urethra, and the reproductive organs